Socket.io: Cannot read property 'emit' of undefined

Question

So i am trying to connect multiple users to a room where video can be shared, but I keep getting an error whenever I join a room which is Cannot read property 'emit' of undefined which is thrown for the socket.to(roomId).broadcast.emit('user-connected', userId) line. I'm not sure what is causing this, and any help would be great. Cheers.

const express = require('express')
const app = express()
const server = require('http').Server(app)
const io = require('socket.io')(server)
const { v4: uuidV4 } = require('uuid')

app.set('view engine', 'ejs')
app.use(express.static('public'))

app.get('/', (req, res) => {
  res.redirect(`/${uuidV4()}`)
})

app.get('/:room', (req, res) => {
  res.render('room', { roomId: req.params.room })
})

io.on('connection', socket => {
  socket.on('join-room', (roomId, userId) => {
    socket.join(roomId)
    socket.to(roomId).broadcast.emit('user-connected', userId)
    // This line here

    socket.on('disconnect', () => {
      socket.to(roomId).broadcast.emit('user-disconnected', userId)
    })
  })
})

server.listen(3000)

Answer 1

If I am right, you are following Web Dev Simplified's Zoom Clone video, I was facing the same issue, but omitting the .broadcast property works fine.

Answer 2

socket.broadcast.to(roomId).emit("user-connected", userId);

It worked for me